Why is Your Check Engine Light On?
Your check engine light is a warning sign.
The issue might be anything from an oxygen sensor to the gas cap.
There are hundreds of causes, codes, and symptoms. Each has multiple fixes. Here is a short list of some of the general issues that can cause the check engine light to come on. Call your local Colorado AAMCO to get a Vehicle Courtesy Check.
- O2 Sensor Needs Replacement
- Spark Plug Wires Replacement
- Mass Air Flow Sensor Malfunction
- Catalytic Converter Replacement
- Loose Gas Cap
Oxygen Sensor
When the oxygen sensor fails, all kinds of things can go wrong.
The oxygen sensor determines the air/fuel mixture that goes into the cylinders for the pistons to push, detonate, and power the engine. The principal of combustion, in this case internal combustion as it applies to your car’s engine, is predicated on oxygen. No air, no combustion, no acceleration. The oxygen sensor analyzes the oxygen flow and fuel mix, and makes adjustments as necessary to make sure the mix isn’t too rich or too lean in the cylinders. The resulting exhaust gases from the combustion in the cylinders pass through the exhaust manifold, where any residual fuel vapor is burned off. The remaining gases then go through the catalytic converter, which converts them into something more environmentally friendly.
Spark Plugs
Spark plugs wear out and can cause the engine to chug, choke, shake, and stall.
As with the oxygen sensor, replacing spark plugs is relatively cheap. Repairing the damage caused if you don’t replace them is expensive. The spark plugs make the air/fuel mixture in the cylinders explode. No sparks, no explosions means no internal combustion in the internal combustion engine – which means you are going nowhere. At best, you’re going slowly, noisily, and inefficiently. Chances are you’ll probably have to replace the ignition coil, too, for around $400. Bonus to all of this: the catalytic converter will probably have to be replaced at this point, as well. It’s sensitive to bad spark plugs. Are you seeing a the connection of all these parts here and how if one goes bad, all kinds of other bad things can happen and cause damage? Time to call AAMCO Colorado.
Mass Airflow Sensor
When this part fails, the engine can act like it does when the spark plugs are bad.
The mass airflow sensor measures the amount of air flowing into the engine and determines how much fuel to add to the mix into the engine. Without the mass airflow sensor the engine can really suffer. It can become hard to start; it will hesitate, drag, or jerk, especially at acceleration; the engine will hiccup or the idle will be too fast or too slow. Without the mass airflow sensor your vehicle’s emissions will increase, and fuel efficiency will decrease.
Catalytic Converter
Catalytic converter is the third most common repair from a check engine light.
Here’s the one and most expensive reason not to ignore the check engine light. The catalytic converter is a part of the vehicle’s exhaust system that works to convert three harmful pollutants into harmless gases. If the catalytic converter starts to malfunction or fails, it can cost $1,000 or more to replace. And for the record, you can’t have your catalytic converter repaired. If it’s bad, it’s bad and just has to be replaced. So, don’t ignore the check engine light. Instead of $200 you didn’t want to pay for that oxygen sensor, you now need $1,000 to $2,000 or your car won’t run.
Gas Cap
Check the gas cap – it might be loose.
Lastly, if the check engine light comes on right after you pull away from the gas station, pull over, turn off the engine, and check that the gas cap is on tight. If it’s loose, tighten it, restart the engine and see if the light comes back on. If the light stays off, you just fixed the problem! That was easy – and cheap!
If the cap is on nice and tight, and the check engine light does come on again, then there is something else wrong. It’s possible the gas cap is loose and won’t go any tighter, is cracked, or has a worn out seal. Get a new gas cap and see if that fixes the problem. If the check engine light doesn’t come on after you replace the fuel cap, you’ve just saved yourself time, money, and many sleepless nights.
AAMCO Colorado Can Help You With All Your Car Care Needs
AAMCO Colorado’s expert mechanics can diagnose that check engine light and run a Vehicle Courtesy Check on your vehicle, including computer codes. We’ll make sure everything is in good working order, note needed repairs or scheduled maintenance, and get you back on the road safely and reliably. Call or come into your locally owned Colorado AAMCO transmission and total car care center today for the best in automotive repairs, maintenance, and customer service.
Ask a Mechanic
If you have any questions or need more information, feel free to submit your question to our Ask A Mechanic service.
Schedule Your Appointment Today
If you have any questions, feel free to call and talk with one of our courteous technicians. Or, fill out the form below to reserve your time, date, and location.